Apparatus for applying thermoplastic markers to roadways



March 3, 1959 c. E. SEARIGHT 2,375,675

APPARATus FOR APPLYING THERMOPLASTIC MARKERS TO ROADWAYS Filed Aug. 20,1956 2 Sheets-Sheet 1 INVENTOR. CHARLES E. SEARIGHIT @g, BY f ATTORNEYC. E. SE A RIGHT APPARATUS FOR APPLYING THERMOPLASTIC MARKERS T0ROADWAYS Filed Aug. 20, 1956 2 Sheets-Sheet 2 INVENTOR CHARLES E.SEARIGHT ATTORNEY United States Patent F APPARATUS FOR APPLYINGTHERMOPLASTIC MARKERS TO ROADWAYS Charles E. Searight, Jackson, Miss.

Application August 20, 1956, Serial No. 604,989

1 Claim. (CI. 9439) This invention relates to roadway markers whichoperate in such manner as .to lay on the roadway a ribbon of white,yellow or other color for traflic control purposes.

It is a desideratum to apply a ribbon of thermoplastic material, such,for example, as polystyrene or natural rosin, because of its greatertoughness, resistance to abrasion, and for other reasons enabling it tocontinue its useful life for a much greater period and obviating thenecessity of frequent replacement or touch-up.

Ditficulty has been experienced in the use of such thermoplastics forthis purpose because of the inability to effect the proper bond oradhesion between the material and the roadway. As a consequence, whenhardened, such material not infrequently cracks so that it soon becomesuseless for the purpose intended. Furthermore, since the cost ofthermoplastic materials is substantially greater than the paintordinarily used for roadway marking, thermoplastics have not been usedto any great extent.

An object is to overcome the above difficulty and to produce a novel andefficient method for applying thermoplastics to a roadway for trafficcontrol in such manner that an effective bond is achieved between thematerial and the roadway, and cracking of the material after it has setup is eliminated.

Another object is to produce a simple and improved apparatus forcarrying out the above method.

For purposes of illustration but not of limitation, an embodiment of theinvention is shown on the accompanying drawings, in which Figure l is aside elevation of an ambulatory roadway marker in accordance with theinvention;

Figure 2 is a top plan view of the apparatus shown in Figure 1; and

Figure 3 is an enlarged fragmentary detailed view showing the manner inwhich the roadway is heated directly in advance of the valve controlledpassage through which the fluid thermoplastic flows upon the roadway.

The illustrated embodiment of the invention comprises a roadway markingapparatus having a substantially rectangular frame of U beams or thelike supported on a pair of rubber-tired wheels 11, disposedrespectively on opposite sides of the frame. At one side of the frameand rearwardly thereof is a caster wheel 12 mounted on an extension 13of the frame. The apparatus is hand propelled and for this purpose, abail-like handle 14 has its lower ends suitably secured to the frame andthe upper cross portion of the handle being suitably positioned so thatthe operator can walk in rear of the apparatus and push it along.

Suitably secured within the apparatus frame 10 is a container 15, theupper portion of which is generally rectangular in cross section and thelower portion of which tapers downwardly in a funnel-like manner 16 toprovide an outlet in the region of the surface of the top of thecontainer.

2,875,675 Patented Mar. 3, 1959 roadway, as will hereinafter appear. Thecontainer 15 is double-walled, and between these walls is suitableinsu'lation 17, such as glass (fibers or the like, for effecting thedesired thermal insulation. A removable top panel closes the upper endof the container, and for keeping the thermoplastic material within thecontainer in a fluid state, a tube .18 covers asubstantial portionthereof in a serpentine-like manner, with the free ends 'of the tubeprojecting upwardly through the closure for the Heat is forced into thetube 18 by a burner 19 which extends into one of the open ends of thetube 18, the exhaust gases being allowed to pass into the atmospherefrom the other open end of the tube- Gas is supplied to the burner 19from a pipe 20 which connects to a gas tank 21 suitably mounted invertical position on :a platform support 22 rigid with the frame. i

The funnel-shaped bottom end 16 of the container has an outletregistering with a valve housing 23, the lower end of which is disposedslightly above the roadway R (see Figure 3). The housing 23 has anoutlet with which an outlet port of a rotary valve 24 is adapted toregister. The valve 24 may be rotated to and from open position by anoperating lever 25 which extends upwardly and rearwardly as indicated onFigure 1, so as to be conveniently manipulated by the operator. Anotched strip 25a on the side of the container is arranged so that thehandle25 may be sprung into one or another notch to hold it either inits' open' or'closed position as desired.

Slightly in advance of the valve housing 23 is disposed a downwardly andrearwardly inclined burner nozzle 26 which, as indicated on Figure 2,flares outwardly at its lower end in order to direct a fan-shaped flamedirectly upon the surface of the roadway R and of a width approximatingthat of the ribbon to be laid upon the roadway. The burner 26 extendsinto a shield or housing 27, the lower end of which is spaced slightlyabove the surface of the roadway. Gas is supplied to the burner 26 by abranch pipe 28 which, as shown, joins the pipe 20.

In order to assist in maintaining the thermoplastic material in thedesired fluid state, another burner 29 directs its flame against therear of the valve housing 23. This burner is disposed within a suitableshield or housing 30 carried by the frame. A branch pipe 31 connects tothe burner nozzle 29 and in this instance is connected to the branch 28.A hand control valve 32 which is disposed adjacent the tank 21 in thisinstance controls the flow of gas to all of the burner nozzles.

It will be understood that as the apparatus is pushed forwardly by theoperator, the thermoplastic flows through the valve 24 and the outletfrom the valve housing 23 and is deposited in ribbon form upon theroadway R, as indicated at S in Figure 3. The width of the orifice inthe valve housing and valve is such as to obtain a ribbon S of thedesired width. The flow of material can be readily controlled bymanipulating the valve operating arm 25.

An important feature of this invention resides in directing the flameupon the roadway in advance of the ribbon and of such intensity that allor practically all surface moisture is driven from the roadway. Thiscontributes substantially to obtaining a satisfactory bond between thethermoplastic and the roadway. Additionally, by heating the roadway inthis manner, premature setting up of the hot thermoplastic material isprevented. The thermoplastic material enters the interstices andirregularities in the roadway so as to provide a smooth and uniformribbon. Since the material enters all of these small depressions, holesand irregularities in the roadway, cracking of the material is obviated,particularly since there is no bridging by the material. Empirically itis found that by applying the thermoplastic ribbon in this manner, anextremely satisfactory bond is achieved and the material will stand upfor an extended period of time without cracking, chipping or comingloose from the roadway.

Numerous changes in details of construction, arrangement and choice ofmaterials may be eflected without departing from the spirit of theinvention, especially as defined in the appended claim.

What I claim is:

Apparatus for applying a rapidly freezing thermo-plastic material forroadway marking purposes and the like, comprising an ambulatory supportincluding a chassis having ground-engaging wheels on respectivelyopposite sides thereof, a container disposed between said wheels on saidchassis, a gaseous fuel burner having a manifold disposed in saidcontainer for heating said thermo-plastic material disposed therein,said container having a downwardly tapering lower portion formed of adownwardly and rearwardly inclined front wall and a downwardly andforwardly inclined rear wall, said lower portion terminating in a bottomwall having an outlet opening therethrough, a valve casing dependingfrom said bottom Wall, said valve casing having an inlet opening in theupper portion thereof communicating with the outlet opening through ithe bottom wall of the container, the lower portion of said valve casingbeing generally cylindrical and defining a cylindrical valve chamberwith the cylindrical axis extending generally transverse of the chassis,the bottom of 30 ing almost directly therefrom onto the roadway, saidvalve having diametrically opposed through-ports, means on the exteriorof said valve casing for rotating said valve for selectively permittingand blocking the flow of material to said outlet port, a front gaseousfuel burner on said chassis, said front burner lying beneath thedownwardly and rearwardly inclined front wall of the lower portion ofsaid container and being disposed to direct a blast of flame directlydownwardly onto the roadway immediately in front of the lower portion ofsaid valve casing, the flame blast from said front burner occupying thearea contiguous to and immediately in front of the bottom of said valvecasing, and a rear gaseous fuel burner on said chassis, said rear burnerlying beneath the downwardly and forwardly inclined rear wall of thelower portion of said container and being disposed to direct a flameblast downwardly and forwardly onto the rear side of the lower portionof said valve casing, a small portion of the last-named flame blastimpinging on the stream of material from the valve outlet portsubstantially at the point of deposit thereof on the roadway, wherebythe roadway contiguous to and immediately in front of the point ofdeposit, the valve casing, and the stream of material issuing from theoutlet port are all enveloped in an environment of the flame blasts.

References Cited in the tile of this patent UNITED STATES PATENTS881,035 Thwaite Mar. 3, 1908 1,122,384 Grasso Dec. 29, 1914 1,399,681Austin Dec. 6, 1921 1,726,832 Hollingshead Sept. 3, 1929 2,420,410Blankner May 13, 1947 2,578,080 Middlestadt Dec. 11, 1951

